Whetstone



FIG. 1 is a top perspective view of a whetstone showing our new design;

FIG. 2 is a bottom perspective view thereof;

FIG. 3 is a side elevational view thereof;

FIG. 4 is a bottom plan view thereof; and

FIG. 5 is a front elevational view thereof.

The ornamental design for a whetstone, as shown and described.